This invention relates to an improved reinforced filament tape. More particularly, this invention relates to a reinforced filament tape having a high tensile strength and requiring a reduced amount of adhesive material.
A threshold of common demoninator of almost all pressure senstive adhesive tapes is the function of providing adequate strength when in use as a fastening means. To this end, tapes have commonly assumed a form in which a layer of pressure sensitive adhesive is applied to one surface of a backing member. A wide variety of mateials have been used as backing members for tapes such as paper, cloth, and plastic film. Also, various kinds of pressure sensitive adhesive materials have been developed over the years. Some of the more commonly known adhesive materials are natural rubbers, butadiene-styrene and substituted styrene copolymers, poylchloroprene, polyisbotylene and butadiene/acrylonitrile materials.
In certain instances, it has been found desirable to provide a reinforced filament tape which requires a relatively small amount of pressure sensitive adhesive material. Adhesive materials are often expensive, and a reduced amount of adhesive material contributes to a decreased overall cost of the production of the tape. Also, the time required for the adhesive material to dry after application to the backing layer is related to the thickness of the adhesive layer so that a relatively thin film of adhesive increases the speed with which the tape can be produced.
The specialty tape industry has still another important reason for desiring a tape which requires a relatively thin layer of adhesive material. In the appliance industry it is not unusual for items such as refrigerators, ovens, and the like to be shipped and stored with component parts fixed in place within the appliance by means of reinforced tape. These component parts may include trays, drawers, racks, etc. It has been found that tapes having a relatively thick adhesive layer frequently emit offensive odors as components of the adhesive tape volatilize. Thus, it is not uncommon for a refrigerator or other appliance within which a tape having a thick adhesive layer has been used to have an objectionable odor after transport and storage, and this odor may be transferred to food items placed into the appliance during the initial use by the consumer.
Further significant problems occasioned by the tape industry involve the handling and manipulation of reinforced filament tapes. Reinforced filaments generally provide increased strength to the tape and may comprise materials such as Fiberglas.RTM., Nylon.RTM., Rayon.RTM., polyester and the like. These filaments generally extend over the backing layer in a random mat or a spaced parallel arrangement either on an adhesive side or on a release layer side of a backing layer. It has been determined that when the reinforced filaments are placed on the adhesive layer side of the backing material, a substantially greater amount of adhesive material is required for suitable performance because the adhesive material must cover not only the reinforcing filaments and the interstices between the filaments but also be thick enough to form a secure bonding surface. As noted above, however, the use of an increased amount of adhesive material is costly, results in a longer drying time for the tape, and results in a tape which emits a relatively strong offensive odor.
Another problem associated with reinforced filament tapes in which the reinforcing filaments are positioned on the adhesive side of the tape is the relatively large degree of delamination which occurs upon unreeling of the tape or upon removal of the tape from a container. If delamination occurs during unreeling, the tape must be cut, the unreeled portion thrown away and a new section unreeled. If delamination occurs during use wherein a portion of the reinforcing strands and adhesive remain on the container surface upon removal of the backing layer, an additional procedure such as scraping or cutting must be performed before the container can be cleanly opened.
An advance in the reinforced filament tape art occurred in the relatively recent past when it was determined that reinforcing filaments could be positioned on the side of the backing layer opposite the adhesive material. In this construction, reinforcing filaments are held in place by a bonding coat which is then overlayed by a release coat of different material so that the tape can be wound upon and dispensed from a spool. Alternatively, the same material can serve as a bonding coat and a release coat.
While reinforcing tape designs such such as noted above, have achieved at least a degree of industry recognition and utilization, room for significant improvement remains. In this regard, several problems have been associated with reinforced filament tapes of the prior art in which the filaments are positioned on the side of the backing layer opposite the adhesive material. These filaments commonly splinter or otherwise become dislodged from the binding layer of the tape which weakens the tpae and, if sufficiently serious, can destroy the usefulness of the tape. Also, tapes disclosed in the prior art are generally covered by an even coat of release material which given the tape a smooth outer surface. This surface is extremely difficult to write on with a pen or pencil and is a handicap to workers in the industry who often desire to leave messages or identifying marks without writing on the container itself.
A further significant disadvantage of prior fiber reinforced tapes has been that these tapes have commonly been very difficult if not impossible to separate or sever without the use of a cutting instrument such as a scissors or knife. The absence of a tape which is severable by hand is burdensome in that a user is required to maintain a cutting tool at a work site.
The problems suggested in the proceeding are not intended to be exhaustive but rather are among many which may tend to reduce the effectiveness of prior fiber reinforced tapes. Other noteworthy problems may also exist, however, those presented above should be sufficient to demonstrate that the fiber reinforced tapes appearing in the prior art have not been altogether satisfactory.